Integrated power supply circuits formed on one or more substrates are becoming more important as packaged device form factors are reduced for greater device mobility and as packaged device density is increased, for example through three-dimensional integrated circuit (3DIC) architectures. Voltage regulators (VRs) often employ inductors (e.g., inductor-capacitor (LC)-buck converters, etc.) because power supply architectures that avoid inductors, such as switched capacitor designs, are often limited to lower powers making them unsuitable for many high density 3DIC applications. Although many on-chip inductor designs exist (e.g., planar or multi-layer spirals, helixes, serpentines, etc.), they are difficult to fabricate with integrated circuits and often require very large areas to achieve inductance values of even a nanoHenry (nH) due to low efficiency numbers.
Fully integrated LC-VRs employing high efficiency inductors are therefore advantageous.